let o = {
  x: 1,
  foo: () => {
    console.log("hello, world");
  },
};
let p = Object.create(o);
p.y = 2;
console.log(Object.keys(p)); // [ 'y' ]
console.log(Object.getOwnPropertyNames(p)); // [ 'y' ]
console.log(Object.getOwnPropertySymbols(p)); // []
console.log(Reflect.ownKeys(p)); // [ 'y' ]
